The National Kidney Disease Education Program group demonstrated that MDRD equation is sensitive to creatinine measurement error, particularly at higher glomerular filtration rates. Thus, MDRD-based eGFR above 60 mL/min/1.73 m2 should not be reported numerically. However, little is known about the impact of analytical error on CKD-EPI-based estimates. This study aimed at assessing the impact of analytical characteristics (bias and imprecision) of 12 enzymatic and 4 compensated Jaffe previously characterized creatinine assays on MDRD and CKD-EPI eGFR. In a simulation study, the impact of analytical error was assessed on a hospital population of 24 084 patients. Ability using each assay to correctly classify patients according to chronic kidney disease (CKD) stages was evaluated. For eGFR between 60 and 90 mL/min/1.73 m2, both equations were sensitive to analytical error. Compensated Jaffe assays displayed high bias in this range and led to poorer sensitivity/specificity for classification according to CKD stages than enzymatic assays. As compared to MDRD equation, CKD-EPI equation decreases impact of analytical error in creatinine measurement above 90 mL/min/1.73 m2. Compensated Jaffe creatinine assays lead to important errors in eGFR and should be avoided. Accurate enzymatic assays allow estimation of eGFR until 90 mL/min/1.73 m2 with MDRD and 120 mL/min/1.73 m2 with CKD-EPI equation. [less ▲]

Background: Sclerostin is a potent inhibitor of bone formation, but the meaning of its serum levels remains undetermined. We evaluated the association between sclerostin levels and clinical or biological ... [more ▼]

Background: Sclerostin is a potent inhibitor of bone formation, but the meaning of its serum levels remains undetermined. We evaluated the association between sclerostin levels and clinical or biological data in hemodialyzed patients (HD), notably parathormone (PTH), biomarkers of bone turnover, vascular calcifications and mortality after 2 years. Methods: 164 HD patients were included in this observational study. The calcification score was assessed with the Kauppila method. Patients were followed for 2 years. Results: Median sclerostin levels were significantly (p < 0.0001) higher in HD versus healthy subjects (n = 94) (1,375 vs. 565 pg/ml, respectively). In univariate analysis a significant association (p < 0.05) was found between sclerostin and age, height, dialysis vintage, albumin, troponin, homocysteine, PTH, C-terminal telopeptide of collagen type I, bone-specific alkaline phosphatase and osteoprotegerin, but not with the calcification score. In a multivariate model, the association remained with age, height, dialysis vintage, troponin, homocysteine, phosphate, PTH, but also with vascular calcifications. Association was positive for all variables, except PTH and vascular calcifications. The baseline sclerostin concentration was not different in survivors and non-survivors. Conclusions: We confirm a higher concentration of sclerostin in HD patients, a positive association with age and a negative association with PTH. A positive association with phosphate, homocysteine and troponin calls for additional research. The clinical interest of sclerostin to assess vascular calcifications in HD is limited and no association was found between sclerostin and mortality. [less ▲]

Chronic kidney disease (CKD) is a frequent affection, most often detected by evaluation of the glomerular filtration rate (GFR). Measuring GFR by a reference method is not possible for every single ... [more ▼]

Chronic kidney disease (CKD) is a frequent affection, most often detected by evaluation of the glomerular filtration rate (GFR). Measuring GFR by a reference method is not possible for every single patient, even if these methods are probably underused. However, serum creatinine has several limitations of which clinicians should be aware. Knowing these limitations, creatinine and creatinine-based équations (including other parameters like age, gender and ethnicity) still represent the most used and easiest way to detect and assess CKD. [less ▲]

Background Obesity is a recognized risk factor for both the development and progression of chronic kidney disease (CKD). Accurate estimation of glomerular filtration rate (GFR) is thus important in these ... [more ▼]

Background Obesity is a recognized risk factor for both the development and progression of chronic kidney disease (CKD). Accurate estimation of glomerular filtration rate (GFR) is thus important in these patients. We tested the performances of two creatinine-based GFR estimates, the Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, in an obese population. Methods Patients with body mass index (BMI) > 30 kg/m2 were included. The reference method for measured GFR (mGFR) was 51Cr-EDTA (single-injection method, two blood samples at 120 and 240 min). Both indexed and non-indexed results were considered. Serum creatinine was measured using the IDMS-traceable compensated Jaffe method. Mean bias (eGFR–mGFR), precision (SD around the bias) and accuracy within 30% (percentage of estimations within 30% of mGFR) were calculated for both equations. Results The population included 366 patients (185 women) from two different areas. Mean age was 55 ± 14 years, and mean BMI was 36 ± 7 kg/m2. Mean mGFR was 56 ± 26 mL/min/1.73 m2 (71 ± 35 mL/min without indexation). In the total population, mean bias was +1.9 ± 14.3 and +4.6 ± 14.7 mL/min/1.73 m2 (P < 0.05), and accuracy 30% was 80 and 76% for the MDRD and CKD-EPI equations (P < 0.05), respectively. In patients with mGFR > 60 mL/min/1.73 m2, mean bias was +4.6 ± 18.4 and +9.3 ± 17.2 mL/min/1.73 m2 (P < 0.05), and accuracy 30% was 81 and 79% (NS) for the MDRD and CKD-EPI equations, respectively. Conclusions The CKD-EPI equation did not outperform the MDRD study equation in this population of obese patients [less ▲]

The Cockcroft–Gault equation for estimating glomerular filtration rate has been learnt by every generation of medical students over the decades. Since the publication of the Modification of Diet in Renal ... [more ▼]

The Cockcroft–Gault equation for estimating glomerular filtration rate has been learnt by every generation of medical students over the decades. Since the publication of the Modification of Diet in Renal Disease (MDRD) study equation in 1999, however, the supremacy of the Cockcroft–Gault equation has been relentlessly disputed. More recently, the Chronic Kidney Disease Epidemiology (CKD-EPI) consortium has proposed a group of novel equations for estimating glomerular filtration rate (GFR). The MDRD and CKD-EPI equations were developed following a rigorous process, are expressed in a way in which they can be used with standardized biomarkers of GFR (serum creatinine and/or serum cystatin C) and have been evaluated in different populations of patients. Today, the MDRD Study equation and the CKD-EPI equation based on serum creatinine level have supplanted the Cockcroft–Gault equation. In many regards, these equations are superior to the Cockcroft–Gault equation and are now specifically recommended by international guidelines. With their generalized use, however, it has become apparent that those equations are not infallible and that they fail to provide an accurate estimate of GFR in certain situations frequently encountered in clinical practice. After describing the processes that led to the development of the new GFR-estimating equations, this Review discusses the clinical situations in which the applicability of these equations is questioned. [less ▲]

Background. The role of cholecalciferol supplementation in end-stage renal disease (ESRD) patients has been questioned. The objective of this randomized double-blinded study is to assess whether ... [more ▼]

Background. The role of cholecalciferol supplementation in end-stage renal disease (ESRD) patients has been questioned. The objective of this randomized double-blinded study is to assess whether cholecalciferol therapy can increase serum 25-hydroxyvitamin D [25(OH)D] levels in haemodialysed patients and the safety implications of this therapy on certain biological parameters and vascular calcifications score. Methods. Forty-three haemodialysis patients were randomized to receive placebo or cholecalciferol (25 000 IU) therapy every 2 weeks. The biological parameters, serum calcium, phosphorus, 25(OH)D and parathormone (PTH) levels, were monitored monthly for 12 consecutive months. Vascular calcifications were assessed by lateral X-ray radiography. Results. At baseline, the mean serum 25(OH)D levels were low and similar in both groups. Thirty patients (16 treated and 14 placebo) completed the study: 11 patients died (5 placebo and 6 treated), 1 patient dropped out and 1 patient was transplanted (both from the placebo group). After 1 year, the percentage of 25(OH)D deficient patients was significantly lower in the treated group. None of the patients developed hypercalcaemia. The PTH levels tended to increase over the study period under placebo and to decrease in the cholecalciferol group. The median changes in PTH levels from baseline to 1 year were statistically different between the two groups [+80 (−58 to 153) and −115 (−192 to 81) under placebo and cholecalciferol treatment, respectively, P = 0.02].The calcification scores increased equivalently in both groups (+2.3 per year). Conclusions. Cholecalciferol is effective and safe, and does not negatively affect calcium, phosphorus, PTH levels and vascular calcifications. Additional studies are needed to compare the impacts of nutritional and active vitamin D agents on vascular calcification and mortality. [less ▲]

Background. The new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine-based equation <br />was developed to address the systematic underestimation of the glomerular filtration rate (GFR) by the Modification <br />of Diet in Renal Disease (MDRD) Study equation in patients with a relatively well-preserved kidney function. The <br />performance of the new equation for kidney transplant recipients is discussed. <br />Methods. We analyzed the performances of the CKD-EPI equation in comparison with the MDRD Study equation in <br />825 stable kidney transplant recipients. Bias, precision, and accuracy within 30% of true GFR were determined. GFR <br />was measured by urinary clearance of inulin (n=488) and plasma clearance of 51Cr-EDTA (n=337). <br />Results. Mean measured GFR (mGFR) was 50T19 mL/min/1.73 m2. On the whole cohort, bias was significantly lower <br />for MDRD Study equation compared with CKD-EPI creatinine. This superiority translates into a better accuracy <br />(80% and 74% for the MDRD and CKD-EPI creatinine, respectively). The best performance of the MDRD Study <br />equation is confirmed both in the subgroups of patients with mGFR G60 mL/min/1.73 m2 and between 60 and <br />90 mL/min/1.73 m2. For mGFR 990 mL/min/1.73 m2, there were no significant differences between the two <br />equations in terms of performance. <br />Conclusions. The CKD-EPI creatinine equation does not offer a better GFR prediction in renal transplant patients <br />compared with the MDRD Study equation, even in the earlier CKD stages. [less ▲]